Can anyone give advice on IRQ s a good website for the section of a PC course on settings etc for Jumpers and com 1 com 2 selectors I cann ot get to grips with a proper understanding of this section at all

If you open up the System folder in the Control Panel, the Hardware Manager will show you all installed devices. Clicking on the com ports will allow you to see the current system settings, and if any IRQ's are in conflict.

Generally, going in to setup on a reboot will also allow you to change settings for the com and lpt ports. The age of your computer will have a lot to do with its sensitivity to these settings. Older stuff cannot share IRQ's, while modern computers have little problem with it.

If you're having to jumper your com ports, you might get to the site for the mfr of your motherboard, and see if there isn't some useful information there. If it's a name brand, the mfr should be able to supply information of the computer, no matter how old it is (486's and under, forget it).